Plans for a TPI
 

I am currently in a little bit of a planning stage to get some more power out of my GTA. At the moment I am just sort of tossing around ideas and I would like some input on some of this. Before It happens because I know it will, I am not doing a LS swap, or and LT swap, or at this point a 350 swap. I am going to stay with the 305, at least until it lets go. So here are my plans:

Full bolt ons, Runners, plenum, intake base, intake, headers, y-pipe, high flow cat, and a different cat-back because I am not happy with the one I have on there right now.

In addition to that I want to swap in a 3.42 Disc rear.

Now in addition to all that I want to do a heads and a cam to open it up that much more. Keep in mind I will be keeping all emissions stuff and I want it to be able to pass. Here is where it gets a little tricky. As for a cam I am thinking about using a ZZ4 or equal cam with 1.6 or 1.7 ration roller rockers.

As far as the heads go I have a few options. I have a spare set of 305 TPI heads that need to be cleaned up and ported and swap in a little bigger valves. or I can go with a cast 350 TPI head, or a aluminum corvette 350 TPI head, both of which would at the very least need to be ported. Can the springs on any of those handle a ZZ4 cam?

Or I can go aftermarket with something like the Edelbrock E-street SBC heads. but I am not sure if they have the TPI bolt pattern. I would like to use something that would accept the factory TPI bolt pattern. It's more cost effective for me to open up the TPI base and bolt it on then to have to buy a Vortec style and then still have to port it anyways.

Thats what I have now. Comments and suggestions are more than welcome and if you have a part in mind that would be a good fit and is what I am looking for let me know.

have you considered finding a used tpi supercharger setup? with that and bolt-ons, it would net you more hp than doing heads/cam. And you could still probably run the stock tpi setup(just new tb/injectors) because the boost will overcome some of the flow issues

The thought has crossed my mind. However a heads cam turns out to be cheaper than even a use supercharger setup, I need to do what I want for as little as I can but still buy quaility stuff. If that makes any sense.

I basically can do the heads and cam and only have to buy the cam and lifters if ported 305 heads will do the job. I just don't know if it will. If I have to source a set of 350 TPI heads that still won't cost much and I can port them myself.

How much will all of this run? I know you said no motor swaps but power per dollar, its got to be better in the long run.

Adam I know what you are saying but I am just a little bit tired of the old you can't make power with a 305. It more cost effective now and its different. People don't do it. I wanna be the crazy guy that does it lol

I think I can get good realiable power out of it. Its not gonna be a LS car thats for sure but the car isn't a race car. the power is to make me smile. this car will never see track time

Yeah, yeah, I know... but I gotta say it:

You can make some power with a 305, but it will cost more overall.

Right now a basic GM 350 long block is $1450 to your door.

Even if I got a 350 what I have planned would cost the same plus the cost of the 350.

Here you go. .This guy has been trying to sell this car for a while now. It has everything your looking for. Corvette heads, Forced induction, Ect..

http://southjersey.craigslist.org/cto/3032277236.html

Believe me. I know how you feel about making power with a less then desirable motor. Thats what I did with my 3.8 V6. I Dumped 6000 into it and made 370 rwhp.. After it was all said and done the car would always break and wasnt a reliable street car anymore. If I would have just done a stock 3.8 with Forced induction or just a bolt on LS1 swap it would have made my car more reliable and still make in the 350rwhp range..

'

buy it, and take the drivetrain, ill take the rest from ya lol

My wife would kill me if I got another car. We just picked up a C5 last week..

Now that's a steal...




I have a fully ported 85/86 TPI base if you are interested.

A 91 LB9 with full bolt ons, 3.42s and a stall would be a fun car. Do a little tuning and low 14s maybe even high 13s?

85/86 TPI stuff is no good. has cold start injector.

Im not buying that vette. If I bought that I wouldn't be a live to build the GTA lol. No one has answered the one question I had and that is what can the stock head castings handle as far as a cam? Will they handle the ZZ4 with just port work?

The factory valve spring will not handle the zz4 camshaft especially if you run 1.6 ratio rockers. The 305 barely had .400 lift intake and exhaust. The zz4 has .474 intake and .510 exhaust with 1.5 rockers and .505/.544 respectively with 1.6 rockers.

Ok so new springs too

I don't think factory 305 heads flow that great. Maybe some World S/R Torquer 305s?

WBT I will look into those

Yeah, I think 305 heads have a 58cc chamber so if you use "350" heads with a 64cc or 76cc chamber you will lose a lot of compression.

I had the S/R Torquer 305s on my old Monte - they're basically a cast iron version of the L98 58cc Corvette head. The first motor we built was a stock '87 LB9 bottom end with a Crane 2031 Compucam (.438/.452 lift) and those heads and it made 223 hp and 277 ft. lbs. at the wheels on a lean factory tune.

The World heads will also handle a ZZ4 cam, because the second motor I built was an L98 with the same heads and a ZZ4 cam. The car ran great and made plenty of power with just a 52mm throttlebody, ported plenum and aftermarket runners.

223rwhp out of a heads, cam 305!! Was that a TPI car?? Man I made 225rwhp on a heads and cam 3.8 V6 Firebird.

Bottom line is you want to have fun with your car.. If having a 240rwhp car is good enough for you to have fun then go for your 305 build. For me I would do a Blower on the 305.. Thats very unique and you will make more then 240 rwhp and the sound alone from the blower will bring a smile to your face..

Those heads look nice, thanks for the suggestions I think I may use them. I'm guessing you guys like the cam choice?

look into those heads WBT is talking about. i had them on a 305 loved them. the little 305 i built ran 13.1 on motor and 11.47 with a 150 shot, good luck. i think i still have all the parts list that i put on that motor to run that good. if your interested i could find it for you.

While i haven't had a 305 TPI, I did have an LG4 car, which is a similar engine with a ccc quadrajet.

You want to open up the exhaust (headers, new 3" cat, cat back); reduce parasitic power loss with underdrive pulleys, optimize tuning (PROM), get the intake air in cool and unrestricted, and make sure your trans and rear end are up to snuff.

I would suggest nitrous, but it will kill your trans with all the extra TQ - unless it has already been built. A good buddy went from 14.3 to 13.0 with a 100 shot on a 1989 IROC L98. The car ran 1.69 short times with only Nitto drag radials and no suspension work! Definitely the hardest launching street car I was ever in.

I put a blower on my stock 305 TPI. It was fun! It made 340 RWHP.

Yes, but the cam was an emission legal lame cam (look at the specs I posted), and it still was untuned when dyno'd. It was 15:1 off idle, and like 13.6:1 at WOT. It would have been much better with the ZZ4 cam and a tune lol.

That is bad ass!!